Mobile, remotely controlled robots are becoming increasingly popular for use by the military, SWAT units, and police and fire departments. The applicants' TALON® robot, for example, includes an arm with an end effecter, several cameras, several antennas, and a deployable mast.
Presently, the lower robot arm has only one degree of freedom, i.e. it pitches up and down relative to the robot frame. The upper robot arm pivots with respect to the lower robot arm via a chain drive on the lower arm.
For certain missions, it would be desirable to turn the lower (hence the entire) robot arm. Robot arms with shoulders which allow the robot arm to turn (yaw) are known but, for robots like the TALON® robot, it can be difficult, due to size and weight constraints, to add a shoulder and the associated motors, transmissions for driving it.
Such robots are used in extremely harsh and hostile conditions and thus any component of the robot, including the robot arm assembly, must be fairly robust. Also, it may be undesirable, in some instances, to pivot the upper robot arm with respect to the lower robot arm via a chain drive.
There is also a need to be able to manually stow the arm quickly in order to place the robot in a vehicle. But, it is preferable that the arm remain in position even when its motors are not energized to save battery power.